Atherosclerotic heart disease has been shown to have its origins in childhood and young adult life. This competitive continuation application will examine, in young adults, the role of electron beam computed tomography (EBCT) in detecting the presence and quantity of coronary artery calcification (CAC), a marker of the atherosclerotic process. We will further examine the relationship of CAC to coronary risk factor (CRF) levels in the study participants. CRFs have been established by measuring levels of potential factors in middle- and older-aged adults and determining which predict morbidity and mortality from atherosclerotic cardiovascular disease, including coronary artery disease, cerebrovascular disease, and peripheral vascular disease. The Muscatine Study of school age children, which began almost 25 years ago, provides a unique longitudinal population for study of CRF obtained during childhood and young adult life with respect to their predictive value for the development and progression of the atherosclerotic process in the fourth decade of life. By the end of the current funding period, we will have examined 800 young adults who had CRF levels measured at least once during childhood and once during young adult life. Each will have EBCT scans and repeat CRF determinations. In the young adults examined to date, we established that 31% of males and 10% of females, ages 29 to 37 years, have CAC, detected by EBCT; and we have shown that childhood and young adult CRF levels, particularly high body mass index, high blood pressure, high LDL cholesterol and low HDL cholesterol, are significantly related to the presence of CAC. In this continuation we propose to further examine the relationship of CRF levels measured in childhood and young adult life to: 1) CAC measured in young adult life, and 2) the change, i.e. progression, in CAC over a period of four to five years. We will repeat EBCT studies on each of the 800 young adults examined during the initial funding period, and 100 additional female young adults identified during the first year of the continuation. In this longitudinal study, we will be able to characterize the factors associated with progression of atherosclerosis in an asymptomatic population. The presence of documented cardiovascular- related death in 3,000 adult relatives (siblings, parents, grandparents, aunts and uncles) of the young adults will be characterized. Results from these investigations may establish whether CAC, detected in young adult life, identifies high risk families. These studies will further define the relevance of CAC as an indicator in asymptomatic young adults of accelerated atherosclerosis.